VERTIGO. 251 



Isthnia bolleslana, Morse, Ann. N. Y. Lye. VIII, 209, f. 4-G (Nov. 1SC5). 

 Vertigo bollesiana, Moese, Amer. Nat. I, (5(39, f. 63-(J4 (1868). 



New England ; New York ; Virginia. 



Buccal plate of the same width throughout, slightly rounded 

 at the ends ; cutting edge without projections, 

 finely striated. Fig. 439. 



Lingual membrane with 88 rows of (12— 1—1 2) /<tllli 1 lUii^ 

 teeth ; central and lateral plates notched at outer 



Jaw of Vertigo 



posterior corners ; central plate square, widening boiiestana. [Morse] 

 posteriorly, armed with three minute denticles, 

 central one largest ; laterals having two minute denticles apart, 

 outer denticle nearly obsolete ; unciui scarcely notched. 



Fig. 440 



,eflt=3fcfl 



r.-„E,^^^^ 



Lingual membrane of Vertigo bollesiana. [Moese. J 



TertigO miliuni, Gould. — Shell very minute, subcylindrical, 

 diminishing equally to both extremities ; epidermis dark amber, or chest- 

 nut color; whirls five, rounded, very minutely striated, decreasing slightly 

 to the apex, which is obtuse ; suture deep ; peristome wliite, slightly re- 

 flected ; aperture lateral, half the width of the last whirl, withiu brownish, 

 general shape semicircular, truncated abruptly and directly 

 by the last whirl, a testaceous deposit upon which forms the Fig. 441. 

 transverse margin, and connects the two extremities of the 

 peristome ; circumference made up of two curves of different 

 radius uniting in the peristome, where the junction causes an 

 angle projecting inwards, the smaller curve comprising about 

 cue-fourth part, and forming the superior portion of the peri- 

 stome ; teeth six, two on the transverse margin, sharp, pro- 

 jecting, and tooth-like ; one in the angle between the colu- 

 mellar and transverse margins, broad, massive, and prominent, with 

 occasionally one or more tnben-les about its base; one on the lower part 

 of the columellar margin; two on the peristome, in the base of the aper- 

 ture, and at the junction of the two curves; umbilicus rather wide. 

 Length f, diam. f mill. 



Pupa milium, Gould, Bost. Journ. Nat. Hist. Ill, 402, pi. iii, f. 23 (1840) ; 

 IV, 359 (1843) ; Invert.-brata, 187, f. 118 (1841).— DeKay, N. Y. 

 Moll. 48, pi. iv, f. 44 (1843). — Adams, Vermont Mollusca, U7 

 (3 842).- Pfeiffer, Mon. Hel. Viv. II, 362.— Bihney, Terr. Moll. II, 

 337, pi. Ixxi, f. 1.— KiJSTER, in Chemnitz, ed. 2, 119, pi. xv, f. 39-42. 



